SALT LAKE CITY — Members of an alleged secretive drug-trafficking organization that represents itself as a music group have been charged with conspiracy to distribute meth, according to court documents unsealed Friday.

In all, 15 Salt Lake valley residents have been charged in federal court, according to court documents. Of those, 12 were arrested Tuesday, and arrest warrants are out for the other three.

The defendants were allegedly part of a group called Glenmob, which U.S. Attorney's Office spokeswoman Melodie Rydalch said "is a hybrid street gang with association with other street gangs."

State and federal authorities "determined Glenmob, while identifying themselves as a music group, were involved in several violent crimes in Utah," Rydalch said in a statement.

"(Investigators) suspected the music group of being a front for narcotics distribution," she said.

Rydalch added that "Glenmob frequently posts music videos on YouTube."

"The FBI identified many of those in the videos as suspected and known narcotics traffickers," she said.

The defendants are each charged with conspiracy to distribute methamphetamine. Federal prosecutors say that in the case of a conviction, the charge would carry a 10-year mandatory minimum sentence and up to life in prison.

The U.S. Attorney's Office; FBI; Bureau of Alcohol, Tobacco, Firearms and Explosives; Unified police; Salt Lake police; and West Valley City police spoke at a Friday press conference announcing the charges.

The arrests carried out Tuesday yielded 15 pounds of meth, a half-pound of heroin and several pounds of marijuana, according to John Huber, U.S. Attorney for the District of Utah. Police also reported seizing 15 firearms, three vehicles and $36,000 in cash.

More notable than the scope of Glenmob's alleged drug trafficking, Huber said, was their "operational security" that was difficult to pierce.

"How security conscious this group has been, how close-knit they are," he said in an interview, "that was a real challenge."

Rydalch said the charges filed this week indicate that "Glenmob is a very tight organization and rarely communicates with individuals outside their established circle."

"Leaders distribute to a (minimal) number of buyers in an effort to avoid law enforcement penetration into the organization," she said.

"There will be a palpable positive impact on public safety in the state of Utah" as a result of the arrests, he said.

Eric Barnhart, special agent in charge of the Salt Lake City Division of the FBI, agreed.

"For every ounce that's trafficted, the good people, the good communities in the (Salt Lake) Valley are put at risk," Barnhardt told reporters.

Salt Lake County Sheriff Rosie Rivera said that beginning last fall, investigators from various agencies began focusing their resources on "a significant increase in violent crime on the west side" of the county. Ultimately, that investigation led to zeroing in on the havoc allegedly wrought by members of Glenmob, she and Huber said.

"Our citizens in the Kearns, Magna area ... told us 'we need help out there,'" Rivera said. "That was our goal, and I know that this is going to have a huge impact on (the) violent crime in the west side."

Kearns and Magna residents said "they wanted help and they wanted it right now," Huber added.

Huber said the new charges don't mark the end of the investigation into the Glenmob group.

"We seized a lot of evidence this week that we still need to process," he said.

Huber also publicly implored Silva, Molina, and Tapia-Bustamante, whose arrest warrants were outstanding as of Friday afternoon, to "peacefully turn themselves over to law enforcement authorities."